1. Field of the Invention
The present invention relates to a safe having a motor-driven locking mechanism and, more particularly, to a safe having a motor-driven locking mechanism by which the door is locked or unlocked easily and reliably by the rotational force of a drive motor rotating in accordance with the input of an open/close command signal.
2. Description of the Prior Art
Safes are used in various places for the purpose of keeping money, valuables and important papers. Particularly, hotels and the like require a safe for each room which is easily locked or unlocked by the guest.
A conventional personal safe of this kind for hotels adopts the structure in which the door is locked or unlocked by turning the key. Such a key-operated safe, however, is troublesome because the user must keep the key every time. In addition, since such a safe is comparatively easy to unlock, it involves a danger of being robbed.
Personal safes having a motor-driven locking mechanism have recently been put to practical use. This kind of safe is advantageous in that since the drive motor for locking/unlocking the door is controlled by the open/close command signal followed by an appropriate password, there is little possibility of being robbed.
If the command signal for the drive motor is supplied by the input of the registered number by means of a keyboard or the like, the hotel guest or the like need not always take the safe key with him. Due to these conveniences, safes having a motor-driven locking mechanism gain public favor.
Such a conventional safe having a motor-driven locking mechanism, however, has some problems. For example, it is comparatively difficult to appropriately combine the motor for driving locking mechanism by an electrical command signal with a lock bolt having an adequate mechanical rigidity and used for locking/unlocking the door, which fact often causes a mechanical trouble in the safe.
Conventionally, when the lock bolt is directly driven by the motor, the main shaft of the motor and the lock bolt are generally directly connected by an eccentric cam or the like, so that the distance of travel of the lock bolt is controlled by the amount of rotation of the motor either by using the rotation of the motor itself or converting it into the linear movement. It is therefore often the case that the rotation of the motor is not transmitted accurately due to the grating of the lock bolt or the like.
In addition, since the amount of rotation of the motor directly determines the distance of travel of the lock bolt, it is necessary to control the rotation of the motor with accuracy, and a large-sized motor having a large driving torque and high capacity of controlling the amount of rotation is required, thereby inconveniently increasing the size of the locking mechanism.